class MyHashSet {
public:
    vector<int>arr;
    MyHashSet() {
        
    }
    void add(int key) {
        arr.push_back(key);
    }

    void remove(int key) {
        for (int i = 0; i < arr.size(); i++) {
            if (arr[i] == key) { arr.erase(arr.begin() + i); i--; }
        }
    }

    bool contains(int key) {
        for (int i = 0; i < arr.size(); i++) {
            if (arr[i] == key) { return true;}
        }
        return false;
    }
};